Phenotypic and genotypic diversity in Neisseria gonorrhoeae: Using population biology to understand antimicrobial resistance and pathogenesis

抗生素耐药性的全球蔓延对全球人类健康构成了日益严重的重大威胁。日益增加的威胁之一是性传播疾病淋病，许多国家都报告了最后手段治疗失败（即第三代头孢菌素）的情况。世界卫生组织强调，淋病可能很快就会变得无法治疗，因为目前没有疫苗或新药可用。淋病奈瑟菌的致病菌群结构复杂且非克隆，这是由于在分离株之间发生了高水平的基因重组。多产的基因重组可能会使淋球菌群体研究陷入混乱，特别是此类研究往往集中于有限的基因数量，如多位点序列分型（MLST）。遗传可塑性允许淋球菌通过基因分期重组快速产生一系列表型，其中最适合的可以在体内选择，促进在被这些细菌感染的不同粘膜生态位内的快速适应。本博士旨在分析不同粘膜部位的淋球菌分离株的抗生素耐药性，并研究这些分离株的基因组和毒力相关表型。这些性状与感染传播动力学的联系将通过数学建模进行检验。成功的候选人将通过不同的免疫分析和蛋白质组学来确定关键毒力因子的存在，并感染具有代表性的男性和女性粘膜表面的细胞系，模拟各种临床分离的Ng在体内培养条件。将检测临床相关抗生素的最低抑菌浓度（mic）。对于每个分离株选择，基因组将被测序，并确定任何相关的质粒。最后，MIC、毒力因子存在、基因组多样性和细胞系感染的数据将为数学模型提供信息，以研究潜在的进化机制。结果具有翻译的重要性：我们将提高对与抗菌药物敏感性和毒力相关的体内选择的理解。此外，我们将确定生态位特异性是否是细菌表型的重要考虑因素，然后可以在使用抗菌剂时使用。总的来说，这个项目将提供多学科的培训，并提高我们对淋球菌种群生物学的理解。

The global spread of antibiotic resistance is a significant and increasing threat to global human health.Amongst increasing threats is the sexually transmitted disease gonorrhoea, for which last resorttreatment failures (i.e. third generation cephalosporins) have been reported in numerous countries.The WHO has highlighted that gonorrhoea may soon become untreatable as no vaccine or new drugsare currently available. The population structure of the causative pathogen Neisseria gonorrhoeae iscomplex and non-clonal due to the high level of genetic recombination that occurs between isolates.Prolific genetic recombination can confound population studies on gonococci, especially as suchstudies often focus on limited gene numbers such as Multi-locus sequence typing (MLST). Geneticplasticity allows gonococci to quickly generate a range of phenotypes though gene phasing andrecombination, the fittest of which can be selected for in vivo, facilitating rapid adaptation within thedifferent mucosal niches infected by these bacteria. This PhD aims to profile the antibiotic resistanceof gonococcal isolates from distinct mucosal sites and study the genomic and virulence relatedphenotype of these isolates. Linkage of these traits to the dynamics of infection transmission will beexamined through mathematical modelling. The successful candidate will determine the presence ofkey virulence factors by distinct immunoassays and proteomic, and infect cell lines representative ofthe male and female mucosal surfaces mimicking in vivo culture conditions with a diverse range ofclinical isolates of Ng. Minimal inhibitory concentrations (MICs) for clinically relevant antibiotics willbe assayed. For each isolate selection the genome will be sequenced plus any associated plasmididentified. Finally, data for MIC, virulence factor presence genomic diversity and cell line infectivitywill inform mathematical models to investigate potential evolutionary mechanisms of action.The outcomes are of translational importance: we will improve understanding of in vivo selection inrelation to antimicrobial susceptibility and virulence. In addition, we will identify if niche specificity isan important consideration for bacterial phenotypes that may then be utilised in using antimicrobials.Overall this project will provide multi-discipline training and improve our understanding of gonococcalpopulation biology.